1. Field of the Invention
The present invention relates to an organic light emitting diode, and more particularly, to an active matrix organic light emitting diode (AMOLED) display and method for driving the same, which has a simplified configuration of an emission control signal generating circuit.
2. Description of the Related Art
In recent years, a liquid crystal display (LCD) and an organic light emitting diode (OLED) display are widely used in a portable information terminal due to advantages of light weight, thin size, and the like. The OLED display is being recognized as a next generation flat panel display because it has brightness and viewing angle characteristics superior to the LCD.
Typically, in an active matrix organic light emitting diode (AMOLED) display, one pixel includes R, G and B unit pixels, and each of the unit pixels has an electroluminescent (EL) element. The EL elements have R, G, and B organic emission layers interposed between an anode electrode and a cathode electrode thereof, respectively, which emit light in response to the voltage applied to the anode and cathode electrodes.
FIG. 1 shows a configuration of a conventional AMOLED display 10.
Referring to FIG. 1, the conventional AMOLED display 10 includes a pixel portion 100, a gate line driving circuit 110, a data line driving circuit 120, and an emission control signal generating circuit 190. The pixel portion 100 includes a plurality of gate lines 111-11m provided with scan signals S1-Sm from the gate line driving circuit 110, and a plurality of data lines 121-12n for providing data signals DR1, DG1, DB1-DRn, DGn, DBn from the data line driving circuit 120. In addition, the pixel portion 100 includes a plurality of emission control lines 191-19m for providing emission control signals output from the emission control signal generating circuit 190, and a plurality of power supply lines 131-13n for providing power supply voltage VDD1-VDDn.
In the pixel portion 100, a plurality of pixels P11-Pmn are arranged in a matrix format, and are connected to the plurality of gate lines 111-11m, the plurality of data lines 121-12n, the plurality of emission control lines 191-19m, and the plurality of power supply lines 131-13n. Each of the pixels P11-Pmn includes three unit pixels, namely R, G, B unit pixels PR11, PG11, PB11-PRmn, PGmn, PBmn, and is connected to corresponding ones of the gate lines, the data lines, the emission control lines and the power supply lines.
For example, the pixel P11 includes the R unit pixel PR11, the G unit pixel PG11, and the B unit pixel PB11, and is connected to a first gate line 111 for providing a first scan signal S1 among the plurality of gate lines 111-11m, a first data line 121 among the plurality of data lines 121-12n, and a first power supply line 131 among the plurality of power supply lines 131-13n. 
In other words, the R unit pixel PR11 of the pixel P11 is connected to the first gate line 111, the R data line 121R of the first data line 121 provided with the R data signal DR1, and the R power supply line 131R of the first power supply line 131. In addition, the G unit pixel PG11 is connected to the first gate line 111, the G data line 121G of the first data line 121 provided with the G data signal DG1, and the G power supply line 131G of the first power supply line 131. Further, the B unit pixel PB11 is connected to the first gate line 111, the B data line 121B of the first data line 121 provided with the B data signal DB1, and the B power supply line 131B of the first power supply line 131.
The above-mentioned emission control signal generating circuit 190 includes three emission control signal generating devices for R, G, B, which provide the R, G, B subpixels PR11-PRmn, PG11-PGmn, and PB11-PBmn with emission control signals, respectively, as disclosed in the Japanese Patent Publication No. 2001-60076. Since each of the R, G, B emission control signal generating devices includes a shift register, the number of elements becomes larger and a circuit area also becomes larger. As a result, a failure rate increases and the yield decreases.